Shoe midsole

ABSTRACT

A midsole of a shoe with multiple layers in which at least one of the layers is wrapped in film in order to protect it from the elements, provide stability and also to provide some visual features.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the structure of a midsole for a shoe.More particularly, the present invention relates to a midsole that has asoft layer wrapped in a protective, stabilizing and/or decorative film.

2. Description of the Related Art

Shoes are comprised of an upper, midsole and outsole. Shoes are designedfor many purposes—from protection on the job, to performance duringathletic activity on the track or court, to special occasions andeveryday lifestyle. In order to achieve these purposes, shoes are madewith different types of uppers, midsoles and outsoles that enable themto properly suit the activity. Midsoles are an integral part of the shoeand provide stability and cushioning to the user of the shoe.

A shoe midsole may be designed with various considerations. Some ofthose considerations present limitations and disadvantages. In someapplications, the midsole must have a soft element in order tofacilitate a particular is walking motion. However, due do the softelement, stability is compromised. Furthermore, due to the material thatthe soft element is made out of, the soft part of the midsole can takeon elements, such as water, that may cause chemical reactions and leadto the breakdown of the midsole.

In general, most footwear functions to keep the foot properly andcomfortably positioned, stabilized, and minimizes a tendency toward amedial and/or lateral rolling motion. Prior art midsoles which have asoft lower layer are unstable and therefore usually requirestabilization material such as a shank piece or a relatively hard uppermidsole layer. Prior art shoes have attempted to protect the entiremidsole, but not in a dual durometer, two layer configuration.

Modern midsoles can be comprised of multiple layers. In particular, somemidsoles have layers having different durometers of hardness. A softdurometer layer for cushioning and a firmer durometer layer forstability. Materials used are generally comprised of elastomericmaterials that would include polyurethane, polyester elastomer,fluoroelastomer, chlorinated polyethylene, polyvinyl chloride,chlorosulfonated polyethylene, polyethylene/ethylene vinyl to acetatecopolymer, neoprene, butadiene acrylonitrile rubber, butadiene styrenerubber, ethylene propylene polymer, natural rubber, silicone rubber,polyethylene, synthetic rubber, sulfide rubber, nitrile rubber,halogenated butyl rubber, polyethylene glycol, and combinations thereof.Soft lower layers in general are not used exclusively as they are notstable and could cause discomfort, pain or injury if is not used inconjunction with a stabilization device, such as a shank piece orrelatively hard upper midsole layer to support the lateral to medialmotion of the foot. The stabilization device is made from a more densematerial such as rubber, plastic, thermoplastic, which acts to controlpronation and guide the wearer into the proper gait cycle.

Furthermore, the elastomeric materials used for midsoles include foamsthat are susceptible to damage from the elements that can cause chemicalreactions and lead to breakdown of the midsole. In particular, outsideelements such as extreme heat or cold, hydrolysis, ozone oxidation, UVradiation, and acid rain can cause a chemical breakdown of theelastomeric materials used for midsoles, thus reducing the efficiencyand lifespan of the midsole.

Also, there is difficulty printing intricate patterns on elastomericmaterials used for midsoles and it is costly to change the color of theelastomeric material to represent a different color for each shoe style.

The present invention seeks to provide a soft midsole which is s wrappedin film to protect it from the elements and to increase stability. Thefilm may also add a decorative component to the midsole by having colorsand/or prints on it.

SUMMARY OF THE INVENTION

It is an object of the present invention to have a midsole with a layerthat is relatively soft that is wrapped in an impermeable film such asthermoplastic polyurethane, polyvinyl chloride, or polyolefin.

In a preferred embodiment, the invention includes a midsole that iscomprised of a distinct upper layer and a distinct lower layer. Thelayers may be made of elastomeric materials that would includepolyurethane, polyester elastomer, fluoroelastomer, chlorinatedpolyethylene, polyvinyl chloride, chlorosulfonated polyethylene,polyethylene/ethylene vinyl acetate copolymer, neoprene, butadieneacrylonitrile rubber, butadiene styrene rubber, ethylene propylenepolymer, natural rubber, silicone rubber, polyethylene, syntheticrubber, sulfide rubber, nitrite rubber, halogenated butyl rubber,polyethylene glycol, and combinations thereof.

The lower layer, which may or may not be made of the same material asthe upper layer, has a density that is less than the density of theupper layer and is sufficiently low in density and high incompressibility so as to allow the lower layer to compress and deform ahigher, or greater, amount under a given weight than the upper layerwould compress and deform under that same weight.

Due to the low density of the lower layer, the layer is particularlysusceptible to damage from the elements. Outside elements, if allowed tocontact the lower layer or seep in between the layers may cause chemicalreactions and lead to the breakdown of the midsole. In particular,outside elements such as extreme heat or cold, hydrolysis, ozoneoxidation, UV radiation, and acid rain can cause a chemical breakdown ofthe elastomeric materials used for midsoles, thus reducing theefficiency and lifespan of the midsole.

In order to prevent such damage, the soft lower layer of the midsole iswrapped in film in order to provide protection to that layer from theelements. The film could also provide a new pattern, design or color.

Furthermore, when a soft midsole layer is used in a shoe, the user ofthe shoe may experience excess instability such that the user loses hisbalance and falls down. The wrapping of the soft midsole layer with afilm counteracts this effect. The film confines the soft midsole layerand prevents excess deformation of that layer, thereby enhancingstability.

The wrapping of the soft layer of the midsole in a film is typicallydone during the molding process. The film is positioned into the moldhaving a surface complementary to the desired predetermined surfaceshape of the midsole. The film may be applied in a vacuum mold. Thevacuum mold forms the shape of the film so that it is in the desiredshape of the midsole layer. The elastomeric material that makes up themidsole layer is poured inside the mold and inside the film that isformed to the desired shape of the midsole layer.

The film used in the vacuum mold forming process is formed either to theside or upwards of the midsole layer. Any excess film is then eithertrimmed or folded over onto the top surface of the midsole layer.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example only, selected embodiments and aspects of the presentinvention are described below. Each such description refers to aparticular figure (“FIG.”) which shows the described matter. All suchfigures are shown in drawings that accompany this specification. Eachsuch figure includes one or more reference numbers that identify one ormore part(s) or element(s) of the invention.

FIG. 1 is an exploded view of the midsole.

FIG. 2 is an exploded view of the lower layer and film.

FIG. 3 is a cross section view of the lower layer and film.

FIG. 4 is a cross section view of the lower layer and film.

FIG. 4A is a cross section view of the midsole.

FIG. 5 is an elevation view of the midsole.

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention will now be described with reference to the preferredembodiment shown in FIG. 1. This embodiment shows a midsole 101, theupper layer of the midsole 100, the lower layer of the midsole 102 andthe film 104. As used herein, “above” and “below” refer to relativelocations of identified elements when a shoe and thus the midsole is inits normal, upright position as shown in FIGS. 1 and 5.

The midsole 101, as shown in FIG. 1, comprises an upper layer 100 and alower layer 102. The upper layer 100 may comprise a plurality ofsub-layers. The upper layer 100 has a top surface 113 substantiallyopposite a bottom surface 115. The upper layer 100 has a peripheral wall103. The lower layer 102 has a top surface 117 substantially opposite abottom surface 121. The lower layer 102 has a peripheral wall 105. Asshown in FIGS. 1 and 5, when the midsole is in its normal, uprightposition, the lower layer 102 is below the upper layer 100.

In the preferred embodiment, the upper layer 100 has a first density andthe lower layer 102 has a second density that is less dense than thefirst density. The upper layer 100 has a first compressibility and thelower layer 102 has a second compressibility that is greater than thefirst compressibility. The compressibility of the lower layer 102 isrelatively high. The upper layer 100 is typically made of elastomericmaterials that would include polyurethane, polyester elastomer,fluoroelastomer, chlorinated polyethylene, polyvinyl chloride,chlorosulfonated polyethylene, polyethylene/ethylene vinyl acetatecopolymer, neoprene, butadiene acrylonitrile rubber, butadiene styrenerubber, ethylene propylene polymer, natural rubber, silicone rubber,polyethylene, synthetic rubber, sulfide rubber, nitrile rubber,halogenated butyl rubber, polyethylene glycol, and combinations thereof.However, the upper layer 100 can be made from any other material withoutdeparting from the scope of the present invention. The lower layer 102is made of a compressible and deformable yet resilient material whichmay or may not be the same material of which the upper layer 100 ismade. The upper layer 100 has a bottom surface 115 that may be connectedto the top surface 117 of the lower layer 102 by either friction and/oran adhesive, molding and/or other similar means. However, the upperlayer 100 and lower layer 102 can be connected by other means, notconnected at all, or connected only in part, without departing from thescope of the present invention.

In the preferred embodiment, the bottom surface 121 and the peripheralwall 105 of the lower layer 102 are wrapped by film 104. The film 104may also overlap the peripheral wall 105 and extend to the top surface117 of the lower layer 102. The film may be wrapped by hand, through amolding process, a vacuum molding process or overlay. However, the filmmay be wrapped by other means without departing from the scope of thepresent invention. The film 104 may be made out of polyurethane,polyvinyl chloride, rubber, thermal plastic rubber or thermoplasticpolyurethane. However, the film 100 can be made from any other materialwithout departing from the scope of the present invention. The bottomsurface 121 and peripheral wall 105 are wrapped by film 104, prior tothe lower layer 102 being connected to the upper layer 100.

FIG. 2 is an exploded view of the lower layer 102 and the film 104. Asshown, the film 104 is normally flat or in rolls. The film 104 caneither be translucent, transparent, colored or patterned. The film 104is applied to the bottom surface 121 and peripheral wall 1.05 of thelower layer 102 as described above.

FIG. 3 shows a cross section view of the film 104 combined with thelower layer 102, during the production process. As shown, the film 104overlaps to the side of the lower layer 102 up the peripheral wall 104and can be trimmed or folded over to the top surface 117 of the lowerlayer 102.

FIG. 4 is a cross section view of the film 104 combined with the lowerlayer 102, during an alternative production process. As shown, the filmoverlaps upwards of the peripheral wall of the lower layer 102 and canbe trimmed or folded over to the top surface 117.

FIG. 4A is a cross section view of the film 104 combined with the lowerlayer 102. During the production process, as shown, the film is foldedupwards on the top surface 117 of the lower layer 102.

FIG. 5 is an elevation view of a preferred embodiment of the completemidsole 101. FIG. 5 shows the upper layer 100 placed on top of the lowerlayer 102 and film 104 combined together to form the complete midsole101. The midsole 101 is below a shoe upper (shown in phantom) in acomplete shoe. The midsole 101 is above a shoe outsole (shown inphantom) in a complete shoe.

1. A shoe midsole comprising: A plurality of layers each having asurface substantially opposite the surface on an adjacent layer; whereinat least one layer in the plurality of layers is wrapped by a film. 2.The shoe of claim 1 in which said film is transparent.
 3. The shoe ofclaim 1 in which the film is selected from the group consisting ofpolyurethane, polyvinyl chloride, rubber and thermal plastic rubber orcombination thereof.
 4. The shoe of claim 1 in which the film iscomprised of at least one member of the group consisting ofpolyurethane, polyvinyl chloride, rubber and thermal plastic rubber. 5.A shoe midsole comprising: a plurality of layers; said plurality oflayers comprising an upper layer and a lower layer; wherein said upperlayer and said lower layer each having a density wherein the density ofthe upper layer is denser than the density of the lower layer; and afilm wrapped around said lower layer.
 6. The shoe of claim 4 in whichsaid film is transparent.
 7. The shoe of claim 4 in which the film isselected from the group consisting of polyurethane, polyvinyl chloride,rubber and thermal plastic rubber or combination thereof.
 8. The shoe ofclaim 4 in which the film is comprised of at least one member of thegroup consisting of polyurethane, polyvinyl chloride, rubber and thermalplastic rubber.